Solar power generation circuit including bypass diodes connected in parallel to groups of series connected solar cells

Abstract

The invention relates to a circuit arrangement for power generation with solar cells ( 10 to 32 ). The solar cells are connected in series and in strings ( 34 to 44 ) each of several cells. A bypass diode ( 50 to 60 ) is connected in parallel to each string ( 34 to 44 ). Further diodes ( 64 to 70 ) are connected in parallel to two and/or more bypass diodes of series-connected strings. With this arrangement, the number of current-carrying diodes is considerably reduced when any strings are in shade.

I claim:  
     
       1. A circuit arrangement for power generation from solar cells comprising: 
       a plurality of series connected strings ( 34 ,  36 ,  38 ,  40 ,  42 ,  44 ), each having a plurality of series connected solar cells ( 10 ,  12 ,  14 ,  16 ,  18 ,  20 ,  22 ,  24 ,  26 ,  28 ,  30 ,  32 );  
       a plurality of bypass diodes ( 50 ,  52 ,  54 ,  56 ,  58 ,  60 ) connected in parallel respectively to each of the plurality of strings; and,  
       a plurality of diodes ( 64 ,  66 ,  68 ,  70 ) connected in parallel to at least two of the bypass diodes.  
     
     
       2. Circuit arrangement according to claim  1 , wherein 
       the bypass diodes ( 50 ,  52 ,  54 ;  52 ,  54 ,  56 ;  54 ,  56 ,  58 ;  56 ,  58 ,  60 ) of three series-connected strings ( 34 ,  36 ,  38 ;  36 ,  38 ,  40 ;  38 ,  40 ,  42 ;  40 ,  42 ,  44 ) respectively or three series-connected strings of solar cells ( 10 - 32 ) are connected in parallel to a diode ( 64 ;  66 ;  68 ;  70 ) respectively .  
     
     
       3. Circuit arrangement according to claim  2 , wherein 
       the printed circuit board ( 80 ) with the bypass diodes ( 50  to  60 ) and the diodes ( 64  to  70 ) connected in parallel to them are arranged in a plastic housing ( 78 ).  
     
     
       4. Circuit arrangement according to claim  1 , wherein 
       the bypass diodes ( 50  to  60 ) and the diodes ( 64  to  70 ) connected in parallel to them are preferably Schottky diodes.  
     
     
       5. Circuit arrangement according to claim  1 , wherein 
       the bypass diodes ( 50  to  60 ) and the diodes ( 64  to  70 ) parallel thereto for two or more strings ( 34  to  44 ) of solar cells are arranged on one side of a printed circuit board ( 80 ), and on the other side printed conductors ( 82 ,  86 ,  90 ,  94 ,  100 ,  102 ,  104 ) with connection points ( 80 ,  84 ,  88 ,  92 ,  96 ,  98 ,  102 ,  106 ) for external lines and with plated-through holes for connections of the bypass diodes ( 50  to  60 ) are provided, and wherein metal surfaces as contact faces for the bypass diodes ( 50  to  60 ) and the diodes ( 64  to  70 ) are provided on the surface of the printed circuit board ( 80 ).